1. Field of the Invention
The present invention relates generally to physical connectivity of Ethernet device, and more particularly, to the ability to communicate over the Ethernet using 10 Mbps or 100 Mbps transmission rates over distances that are 5 to 10 times longer then the current standards.
2. Prior Art
Ethernet connectivity based on the 10BASE-T and 100BASE-TX standards (known as IEEE standard 802.3) is one of the most important technologies in the networking industry today. These standards enable Ethernet communication at 10 Mega bits per second (Mbps) and 100 Mbps respectively. To enable this connectivity, a device transferring the generally digital signaling to signals that can be transmitted over larger distances is used. This device is responsible for the physical layer, which is the first layer of the standard communication model, and is often referred to as the PHY device, which is considered to be one of the key components in the Ethernet solution. It is the characteristics of the PHY that determine the system's capabilities to communicate over the distances mandated by the various Ethernet standards.
In the past decade, due to the rapid increase in the use of the Internet, 10/100 Mbps installations of Ethernet ports have increased exponentially, and the trend continues. With Ethernet being for all practical purposes the network solution of choice for enterprises, campus LAN, small offices and home offices as well as other networked industry applications, this trend is even stronger. In turn, these lead to the tremendous demands for 10BASE-T and 100BASE-TX Ethernet PHY devices, both single port and multi-port.
However, it is not only a numbers game for the 10BASE-T and 100BASE-TX, i.e., the number of ports actually installed. There is a strong trend for a demand for new and higher requirements from features and performance. For example, new features like Power-over-Ethernet, automatic cable diagnostics, polarity and medium dependent interface (MDI) and MDI crossover (MDIX) automatic correction, and so on, as well as higher performance requirements on power consumption, footprint, reliability, tolerance on temperature and power supply, surge and electrostatic discharge (ESD) protection, and the like, are commonly required in new Ethernet deployment.
Another important requirement is that of connectivity distance, a challenge facing a significant problem. Due to the fact that 10BASE-T and 100BASE-TX Ethernet standard (IEEE 802.3) was developed almost twenty years ago, the PHY devices developed based on that standard have a driving distance of 100 to 150 meters (without using a repeater), over a shielded or unshielded twisted pair. At that time this was considered a long enough distance for all the foreseeable and practical applications. However, as 10/100 Mbps Ethernet is used in more and more types of environments and scenarios, and the cost and ease of deployment is getting more and more important, the originally specified encoding schemes and the driving distances are hindering efficient deployment in an increasing number of situations. With requirements of up to 300 meters for 100BASE-TX and up to 500 meters for 10BASE-T for Ethernet connectivity, it can easily be shown that the IEEE standard (802.3) cannot support these driving distance requirements.
It would therefore be advantageous to provide a PHY that would be fully backward compatible with the existing 10BASE-T and 100BASE-TX PHY devices, but provide a significantly extended driving distance using a shielded or unshielded twisted pair. It would be further advantageous if such new PHY device would be capable of an auto-negotiation protocol to enable automatic switching between normal and long-range operation.